As rescue workers rooted through the wreckage of the Hilton hotel in Taba looking for more bodies believed to be buried in the rubble, Major General Aharon Zeevi-Farkash told an emergency session of Ariel Sharon's cabinet that the the main attack, a car bomb, bore all the hallmarks of groups linked to al-Qaida.

The blast sheared off 10 floors on one side of the building late on Thursday, a similar outrage to bombings against Israeli or Jewish targets in Tunis and the Kenyan city of Mombasa that were carried out by al-Qaida associates.

Some people were killed in the blast, others crushed in the rubble and some fell to their deaths. Among those killed was at least one young child.

Last night, bulldozers and sniffer dogs were scouring the area. "We are still searching for life, we are digging almost by hand," Major General Yair Naveh told reporters. "Until we reach the bottom of the hotel we may still find people."

Shortly after the Taba attack, blasts at two backpacker hotels in Ras Shitan, further along the Red Sea coast, killed two people and wounded dozens. The bombings sent thousands of Israeli tourists streaming back home from the Sinai peninsula in the midst of a Jewish holiday.

The intelligence assessment was backed by Israel's deputy defence minister, Ze'ev Boim, who said it was unlikely that Hamas or a similar Palestinian group was responsible. He said it appeared to be the work of "international terror groups like al-Qaida or branches of it".

"It is not the kind of attack that we know comes from Palestinian terror organisations," he said.

Mr Sharon did not mention how his government would respond if al-Qaida was responsible, but Israel was frustrated in its efforts to find members of a group that carried out the car bombing of an Israeli-owned hotel in Mombasa two years ago, killing 16 people, including three Israelis.

The Israeli government was quick to make political capital out of the attack by drawing a connection between the Sinai bombings and Palestinian armed groups. It said Israel was the primary target of "global terrorism" motivated by hatred of democracy, peace and moderation.

Mr Sharon said the Sinai attacks were primarily aimed at Jews who "constitute a target for terrorist actions around the world".

"Terrorism doesn't distinguish between countries or peoples," he said. "Terrorism is global and its goal is to attack the free world; therefore, there can be no compromise with terrorism. It must be fought relentlessly, in every way possible."

The Egyptian government spokesman, Magdy Rady, suggested the blasts were a response to the continuing Israeli military assault on northern Gaza which has left nearly 100 Palestinians dead, many of them children and other civilians.

"I think the explosions are very related to what is going on in Gaza," Mr Rady told the Associated Press.

"We condemn these attacks, which have harmed many people. I think it is very probable that there is a link between these three explosions. It is very unlikely they happened by chance."

Hamas in Gaza denied the group was involved by saying it attacked "only in Palestine". Tellingly, there were no celebratory announcements from Gaza City mosques or cheering on the streets in response to the bombings, of the kind that frequently greet the killing of Israeli soldiers.

Israeli officials took the Hamas claim at face value, drawing parallels instead with a 2002 truck bomb outside a synagogue in Tunisia which killed 21 people and the bombing of a Kenyan hotel later that same year.

Egypt's homegrown extremists were also viewed as unlikely suspects yesterday. They have been generally quiet since the massacre of 58 foreign tourists at Luxor in 1997.

That attack provoked a backlash against the extremists by hitting tourism, on which hundreds of thousands of Egyptians depend for their livelihoods. Mass arrests also prompted many Egyptian militants to flee to Afghanistan - among them Ayman al-Zawahiri, who later became Osama bin Laden's deputy.

Zawahiri, who had been the leader of the Egyptian Jihad group, and another Egyptian, Abu-Yasir Rifa'i Taha of al-Gama'a al-Islamiyya, were among the five signatories to Bin Laden's declaration of "jihad against Jews and Crusaders" issued in 1998.

Even so, there were no hints from Egyptian officials yesterday that the Sinai attacks signalled a renewed campaign by either group.

A month ago, the Israeli defence establishment issued a strong warning against travelling to Egypt, particularly the Sinai, because of a "concrete worsening of the terror threat".

Security sources told the Israeli press that the warning was issued after the capture of six Egyptian students who infiltrated Israel intending to launch an attack.

But its impact was diminished by several similar warnings in the past that proved false, and a belief among some Israelis that the security establishment routinely issues alerts so that it is not accused of failing to warn people if there is an attack.

For the first few hours after the Hilton blast, the Egyptian government was in denial, blaming the explosion on gas bottles. But once the scale of the attack was apparent and two other bombings followed, it became impossible to maintain that position.

Israeli officials speculated that the attack was not only aimed at driving Israeli tourists out of Egypt but at disrupting negotiations with Cairo over Mr Sharon's plan to pull Jewish settlers out of the Gaza strip.